For all the talk about closing the Mexican border and ramping up enforcement efforts – or even deporting illegals en masse – a greater force has reversed the tide of illegal immigration: recession. This is hardly surprising, but the Mexican government confirms that the number of emigrants from Mexico to the US has plummeted since the beginning of the recession in the US.

They came to America for the jobs. And now that the jobs have disappeared (especially in construction) the immigrants have too.

What lesson is there to be drawn from this?

First of all, this is not exactly earth-shattering news. The notion that Mexican immigrants come to America just to take advantage of our social services has never been supported by any data – and it usually carries a quasi-racist overtone. Yes, poor Mexican workers DO place a heavy burden on social services in America. But they don’t come to America for the PURPOSE of availing themselves of American social services. They come for the jobs that pay much better than in Mexico.

But another factor is the economic transformation going on in Mexico itself. Since the signing of NAFTA millions of Mexican families have either lost their land or their agricultural jobs. The de-population of the Mexican countryside – dropping from 40% to 30% rural in just 12 years – has served as a significant “push factor” in the increase in illegal immigration in the US. Similar forces have been at work in Central America, where free trade agreements forced the revocation of small farm subsidies. Unable to compete with large agribusinesses (including those that likely imported the swine flu strain into mass-produced hog farms), small farmers in Latin America are forced to move to industrial towns and cities, or head for the USA.

But now that process has reversed itself – not because of new subsidies and trade barriers but because of the loss of US jobs.

Until Mexican workers earn a living (in real wages vis-a-vis cost of living) south of the border, they will continue to come North once the US economy picks up again. NAFTA was supposed to improve the Mexican economy and increase wages on both sides of the line. That may happen over the very long term. But the short term effect up to now – and there is little sign of it changing soon – is that the opposite has occurred: Mexican families have faced even more desperate straits and will do anything to cross into America – regardless of any threat at the border.

The Mexican government is more than happy to see this “surplus labor” escape to America as it prevents social unrest. Without that American safety valve in this recession, however, Mexico may have to finally alter the anti-labor laws that keep Mexican workers relatively impoverished. If Mexico cannot rely on the US to take in its redundant labor supply, it may face large-scale social unrest and, ultimately, a strong push to the Left in Mexican politics (as has happened elsewhere in Latin America). It behooves the Calderon government to think of ways to improve the lives of Mexicans IN Mexico over the short term.